Pole piece, battery cell and electronic equipment

Abstract

The utility model relates to the technical field of battery cells, in particular to a pole piece, a battery cell and electronic equipment. The pole piece comprises a current collector, a first active substance coating layer, a second active substance coating layer and a third active substance coating layer, the current collector comprises a first wall surface, the first active substance coating layer is arranged on the first wall surface, the first active substance coating layer is provided with a first concave part, the second active substance coating layer is arranged on the first active substance coating layer, and the third active substance coating layer is arranged on the second active substance coating layer. The second active material coating layer is arranged on the first active material coating layer and fills the first concave part, the second active material coating layer is provided with a second concave part, and the third active material coating layer is arranged on the second active material coating layer and fills the second concave part. The ion diffusion rate of the material of the third active material coating layer is higher than the ion diffusion rate of the materials of the second active material coating layer and the first active material coating layer. The battery cell and the electronic equipment comprise the pole piece. According to the utility model, the fast charging performance of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery cores, and in particular to a pole piece, a battery core and an electronic device. Background Art

[0002] As a new type of secondary battery, lithium-ion batteries offer advantages such as high energy and power density, high operating voltage, light weight, compact size, long cycle life, excellent safety, and environmental friendliness. They hold broad application prospects in portable appliances, power tools, large-scale energy storage, and electric transportation power sources. With the rapid development of lithium-ion battery technology, market demands for increasingly higher performance are demanding not only high energy density but also fast charging speeds.

[0003] In order to simultaneously meet the characteristics of lithium-ion batteries with high energy density and fast charging, in addition to improving materials to achieve fast charging, improvements can also be made in the process, such as using a multi-layer coating process. However, in the multi-layer coating process, fast-charging materials and high-capacity materials are layered on each other. Among them, lithium ions migrate very quickly in fast-charging materials, but the lithium insertion speed will slow down when they reach high-capacity materials, which limits the rapid diffusion of lithium ions to the bottom layer, that is, reduces the charging speed of the battery. Utility Model Content

[0004] The main purpose of the present invention is to provide a pole piece, a battery cell and an electronic device, aiming to solve the technical problem in the prior art that the battery cannot be fast charged due to the inability of lithium ions to diffuse rapidly.

[0005] To achieve the above-mentioned purpose, the present invention proposes a pole piece, comprising:

[0006] a current collector, the current collector comprising a first wall;

[0007] a first active material coating layer, the first active material coating layer being disposed on the first wall surface along a first direction, and a first recessed portion being disposed on a side of the first active material coating layer facing away from the first wall surface;

[0008] a second active material coating layer, the second active material coating layer being disposed along the first direction on a side of the first active material coating layer facing away from the first wall surface, the second active material coating layer filling the first recessed portion, and a second recessed portion being disposed on a side of the second active material coating layer facing away from the first active material coating layer;

[0009] a third active material coating layer, the third active material coating layer being disposed along the first direction on a side of the second active material coating layer facing away from the first active material coating layer, and the third active material coating layer filling the second recessed portion;

[0010] The ion diffusion rate of the material of the third active material coating layer is higher than that of the material of the second active material coating layer, and the ion diffusion rate of the material of the second active material coating layer is higher than that of the material of the first active material coating layer.

[0011] In some embodiments, the capacitance of the material of the first active material coating layer is higher than the capacitance of the materials of the second active material coating layer and the third active material coating layer.

[0012] In some embodiments, the first recessed portion extends from one end of the first active material coating layer to the other end opposite to the first active material coating layer along the width direction of the electrode piece; the second recessed portion extends from one end of the second active material coating layer to the other end opposite to the second active material coating layer along the width direction of the electrode piece.

[0013] In some embodiments, the first recessed portion extends from the first active material coating layer to the first wall surface along the first direction; and the second recessed portion extends from the second active material coating layer to the first active material coating layer along the first direction.

[0014] In some embodiments, the first recessed portions and the second recessed portions are alternately arranged.

[0015] In some embodiments, the first recessed portion extends along a straight line from one end of the first active material coating layer to the other end opposite the first active material coating layer; the second recessed portion extends along a straight line from one end of the second active material coating layer to the other end opposite the second active material coating layer;

[0016] The groove width W1 of the first recessed portion satisfies: 0.5um≤W1≤2000um; the groove width W2 of the second recessed portion satisfies: 0.5um≤W2≤2000um.

[0017] In some embodiments, the first active material coating layer is provided with a plurality of first recessed portions along the length direction of the pole piece; the second active material coating layer is provided with a plurality of second recessed portions along the length direction of the pole piece;

[0018] The groove spacing L1 between two adjacent first recessed portions satisfies: 0.5 mm ≤ L1 ≤ 8 mm; the groove spacing L2 between two adjacent second recessed portions satisfies: 0.5 mm ≤ L2 ≤ 8 mm.

[0019] In some embodiments, the coating thickness D1 of the first active material coating layer satisfies: 3.5um≤D1≤60um; the coating thickness D2 of the second active material coating layer satisfies: 2um≤D2≤60um; and the coating thickness D3 of the third active material coating layer satisfies: 2um≤D3≤60um.

[0020] Correspondingly, the present invention also provides a battery cell comprising the pole piece described in any of the above embodiments.

[0021] Correspondingly, the present invention also provides an electronic device, comprising and applying the above-mentioned battery cell.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] In the technical solution of the present invention, in order to achieve the fast charging function of the electrode, the electrode is improved in terms of process, that is, the active material layer on the electrode adopts a multi-layer coating process, and the electrode is improved in terms of material, that is, the electrode is coated with multiple layers of active material layers with different ion diffusion rates. The use of this multi-layer coating structure with different active material layers saves raw material costs while enabling rapid migration of lithium ions within the electrode, thereby achieving the fast charging (quick charging) function of the electrode.

[0024] Furthermore, in the present invention, a first recess is formed on the first active material coating layer and the second active material coating layer is filled into the first recess. Since the ion diffusion rate of the material of the second active material coating layer is higher than the ion diffusion rate of the material of the first active material coating layer, the second active material coating layer filled in the first recess provides a rapid ion diffusion channel for lithium ions to diffuse from the second active material coating layer to the first active material coating layer, so that lithium ions can diffuse quickly from the second active material coating layer to the first active material coating layer, thereby realizing rapid migration of lithium ions between layers, which is beneficial to improving the fast charging performance of the electrode. Similarly, by opening a second recess on the second active material coating layer and filling the third active material coating layer into the second recess, since the ion diffusion rate of the material of the third active material coating layer is higher than the ion diffusion rate of the material of the second active material coating layer, the third active material coating layer filled in the second recess provides a rapid ion diffusion channel for lithium ions to diffuse from the third active material coating layer to the second active material coating layer, so that lithium ions can quickly diffuse from the third active material coating layer to the second active material coating layer, realizing rapid migration of lithium ions between layers, which is beneficial to improving the fast charging performance of the electrode.

[0025] In addition, filling the first recessed portion with the second active material coating layer and filling the second recessed portion with the third active material coating layer is beneficial to compensating for the loss of active material in the first recessed portion and the second recessed portion, thereby improving the energy density of the electrode.

[0026] The battery cells and electronic devices using the above-mentioned pole pieces are beneficial to improving the fast charging performance of the battery cells and electronic devices, thereby improving the dynamic performance of the battery cells and electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of the overall structure of a pole piece provided in one embodiment of the present utility model;

[0029] Figure 2 A schematic diagram of the structural parameters of a pole piece provided in one embodiment of the present utility model;

[0030] Figure 3 A cross-sectional view of the structure of the first active material coating layer in the electrode provided by one embodiment of the present utility model;

[0031] Figure 4 A cross-sectional view of the structure of the second active material coating layer in the electrode provided by one embodiment of the present utility model;

[0032] Figure 5 This is a structural diagram of a double-sided active material coating layer in an electrode provided by an embodiment of the present invention.

[0033] Description of Figure Numbers:

[0034] 100-current collector;

[0035] 110-the first wall; 120-the second wall;

[0036] 200-first active material coating layer;

[0037] 210-first recessed portion;

[0038] 300-second active material coating layer;

[0039] 310 - second recessed portion;

[0040] 400-third active material coating layer;

[0041] X - first direction.

[0042] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0045] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or", "and / or" or "and / or" appear in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] As a new type of secondary battery, lithium-ion batteries offer advantages such as high energy and power density, high operating voltage, light weight, compact size, long cycle life, excellent safety, and environmental friendliness. They hold broad application prospects in portable appliances, power tools, large-scale energy storage, and electric transportation power sources. With the rapid development of lithium-ion battery technology, market demands for increasingly higher performance are demanding not only high energy density but also fast charging speeds.

[0047] In order to simultaneously meet the characteristics of lithium-ion batteries with high energy density and fast charging, in addition to improving materials to achieve fast charging, improvements can also be made in the process, such as using a multi-layer coating process. However, in the multi-layer coating process, fast-charging materials and high-capacity materials are layered on each other. Among them, lithium ions migrate very quickly in fast-charging materials, but the lithium insertion speed will slow down when they reach high-capacity materials, which limits the rapid diffusion of lithium ions to the bottom layer, that is, reduces the charging speed of the battery.

[0048] In order to solve the technical problem that the battery cannot be fast charged due to the inability of lithium ions to diffuse rapidly in the prior art, Figures 1 to 4 , an embodiment of the present invention provides a pole piece, which includes a current collector 100, a first active material coating layer 200, a second active material coating layer 300 and a third active material coating layer 400, the current collector 100 includes a first wall surface 110, the first active material coating layer 200 is arranged on the first wall surface 110 along a first direction X, the first active material coating layer 200 is provided with a first recessed portion 210 on a side away from the first wall surface 110, the second active material coating layer 300 is provided along the first direction X The first active material coating layer 200 is disposed on a side facing away from the first wall surface 110, and the second active material coating layer 300 is filled into the first recess 210. A second recess 310 is provided on a side of the second active material coating layer 300 facing away from the first active material coating layer 200. The third active material coating layer 400 is disposed along the first direction X on a side of the second active material coating layer 300 facing away from the first active material coating layer 200, and the third active material coating layer 400 is filled into the second recess 310. The ion diffusion rate of the material of the third active material coating layer 400 is higher than the ion diffusion rate of the material of the second active material coating layer 300, and the ion diffusion rate of the material of the second active material coating layer 300 is higher than the ion diffusion rate of the material of the first active material coating layer 200.

[0049] In this embodiment, the first recessed portion 210 may be a groove structure or a recessed hole structure, and the second recessed portion 310 may be a groove structure or a recessed hole structure.

[0050] Specifically, in this embodiment, in order to achieve the fast charging function of the electrode, the electrode is improved in terms of process, that is, the active material layer on the electrode adopts a multi-layer coating process, and the electrode is improved in terms of material, that is, the electrode is coated with multiple layers of active material layers with different ion diffusion rates. The use of this multi-layer coating structure with different active material layers saves raw material costs while enabling rapid migration of lithium ions within the electrode, thereby achieving the fast charging (quick charging) function of the electrode.

[0051] Furthermore, in this embodiment, by opening a first recess 210 on the first active material coating layer 200 and filling the second active material coating layer 300 into the first recess 210, since the ion diffusion rate of the material of the second active material coating layer 300 is higher than the ion diffusion rate of the material of the first active material coating layer 200, the second active material coating layer 300 filled in the first recess 210 provides a rapid ion diffusion channel for lithium ions to diffuse from the second active material coating layer 300 to the first active material coating layer 200, so that lithium ions can quickly diffuse from the second active material coating layer 300 to the first active material coating layer 200, thereby realizing rapid migration of lithium ions between layers, which is beneficial to improving the fast charging performance of the electrode. Similarly, by opening a second recess 310 on the second active material coating layer 300 and filling the third active material coating layer 400 into the second recess 310, since the ion diffusion rate of the material of the third active material coating layer 400 is higher than the ion diffusion rate of the material of the second active material coating layer 300, the third active material coating layer 400 filled in the second recess 310 provides a rapid ion diffusion channel for lithium ions to diffuse from the third active material coating layer 400 to the second active material coating layer 300, so that lithium ions can quickly diffuse from the third active material coating layer 400 to the second active material coating layer 300, thereby realizing rapid migration of lithium ions between layers, which is beneficial to improving the fast charging performance of the electrode.

[0052] In addition, filling the first recess 210 with the second active material coating layer 300 and filling the second recess 310 with the third active material coating layer 400 is beneficial to compensating for the loss of active materials in the first recess 210 and the second recess 310, thereby improving the energy density of the electrode.

[0053] Furthermore, in this embodiment, when applying the active material layer to the electrode, the first active material coating layer 200 can first be applied to the first wall surface 110 of the current collector 100 by extrusion coating. After the first active material coating layer 200 is applied, a first recessed portion 210 is formed on the first active material coating layer 200. When forming the first recessed portion 210, care should be taken not to damage the current collector 100. After the first recessed portion 210 is formed, the electrode is rolled to achieve the designed compaction. Then, a second active material coating layer 300 is applied to the first active material coating layer 200, and the electrode coated with the second active material coating layer 300 is rolled to achieve the designed compaction. After the electrode is rolled, a second recessed portion 310 is formed on the second active material coating layer 300. When forming the second recessed portion 310, care should be taken not to damage the current collector 100. Finally, the third active material coating layer 400 is coated on the second active material coating layer 300. After the third active material coating layer 400 is coated, the electrode is rolled as a whole to achieve the designed density of the electrode, and then the remaining manufacturing processes of the electrode are carried out.

[0054] It should be noted that the coating order of the active material coating layer, the grooving order of the first recessed portion 210 and the second recessed portion 310, and the rolling order of the pole piece can be adaptively adjusted. For example, for example, the pole piece can be rolled last after the three layers of active material coating layers are coated and the first recessed portion 210 and the second recessed portion 310 are opened.

[0055] Furthermore, in this embodiment, when the first active material coating layer 200 and the second active material coating layer 300 are grooved, the first recessed portion 210 and the second recessed portion 310 may be formed by laser cleaning, mechanical scraping, or punching.

[0056] Further, in some embodiments, referring to Figure 5The current collector 100 may also be coated with an active material coating layer on both sides. For example, the current collector 100 may further include a second wall surface 120 disposed opposite the first wall surface 110. The second wall surface 120 may be coated with a first active material coating layer 200, a second active material coating layer 300, and a third active material coating layer 400. The coating method of the first active material coating layer 200, the second active material coating layer 300, and the third active material coating layer 400 disposed on the second wall surface 120 may be the same as the coating method of the first active material coating layer 200, the second active material coating layer 300, and the third active material coating layer 400 disposed on the first wall surface 110. That is, the active material coating layers coated on the first wall surface 110 and the second wall surface 120 have a symmetrical structure. The current collector 100 adopts a structure in which the active material coating layer is coated on both sides, which is conducive to improving the energy density of the electrode.

[0057] In some embodiments, the capacitance of the material of the first active material coating layer 200 is higher than the capacitance of the material of the second active material coating layer 300 and the third active material coating layer 400 .

[0058] Specifically, in this embodiment, the material of the first active material coating layer 200 has a higher capacitance than the material of the second active material coating layer 300 and the material of the third active material coating layer 400, that is, the first active material coating layer 200 can store more lithium ions per unit mass. Under the premise of being able to store the same amount of lithium ions, if more lithium ions can be stored per unit mass, the volume can be designed to be smaller accordingly. That is, under the premise of meeting the high capacity and fast charging performance of the electrode, the electrode can be designed to be lighter, thinner and more portable, thereby improving the user experience.

[0059] In some embodiments, reference Figure 3 and Figure 4 The first recessed portion 210 extends from one end of the first active material coating layer 200 to the other end opposite to the first active material coating layer 200 along the width direction of the electrode piece; the second recessed portion 310 extends from one end of the second active material coating layer 300 to the other end opposite to the second active material coating layer 300 along the width direction of the electrode piece.

[0060] Specifically, in this embodiment, since the length of the electrode in the width direction is shorter than the length in the length direction, the first recessed portion 210 and the second recessed portion 310 are opened along the width direction of the electrode, which can shorten the opening length of the first recessed portion 210 and the second recessed portion 310. When the first recessed portion 210 and the second recessed portion 310 are actually processed, no matter which processing method is selected (including but not limited to laser cleaning or mechanical scraping or punching), the shorter processing path is conducive to improving the processing accuracy of the first recessed portion 210 and the second recessed portion 310, and is conducive to reducing the processing difficulty of the first recessed portion 210 and the second recessed portion 310. In addition, the shorter processing path also has lower requirements on equipment, which is conducive to saving the production cost of the electrode and improving the economic benefits of the electrode.

[0061] In some embodiments, reference Figure 1 and Figure 2 The first recessed portion 210 extends from the first active material coating layer 200 to the first wall surface 110 along the first direction X. The second recessed portion 310 extends from the second active material coating layer 300 to the first active material coating layer 200 along the first direction X. For example, the first direction X may be the thickness direction of the electrode sheet.

[0062] Specifically, in this embodiment, the first recessed portion 210 passes through the first active material coating layer 200. When the first recessed portion 210 is filled with the second active material coating layer 300, the second active material coating layer 300 can be directly embedded in the first wall surface 110 of the current collector 100, thereby forming a lithium ion channel that directly passes through the second active material coating layer 300 to the underlying current collector 100. In this way, when charging, lithium ions can quickly diffuse to the underlying current collector 100 of the electrode, thereby helping to improve the fast charging performance of the electrode. Similarly, the second recess 310 passes through the second active material coating layer 300. When the second recess 310 is filled with the third active material coating layer 400, the third active material coating layer 400 can be directly embedded in the first active material coating layer 200, thereby forming a lithium ion channel from the third active material coating layer 400 to the first active material coating layer 200. In this way, when charging, lithium ions can quickly diffuse to the first active material coating layer 200, and then diffuse from the first active material coating layer 200 to the underlying current collector 100, which is beneficial to improving the fast charging performance of the electrode.

[0063] The above structure is beneficial to increasing the diffusion speed of lithium ions between layers and accelerating the migration speed of lithium ions between layers, thereby improving the fast charging performance of the electrode.

[0064] In some embodiments, reference Figure 1 and Figure 2The first recessed portion 210 and the second recessed portion 310 are arranged alternately. That is, the first recessed portion 210 and the second recessed portion 310 are not arranged opposite to each other.

[0065] Specifically, in this embodiment, since the first recessed portion 210 and the second recessed portion 310 are filled with active materials having a higher ion diffusion rate, (for example, the first recessed portion 210 is opened on the first active material coating layer 200, and the first recessed portion 210 is filled with the second active material coating layer 300, the ion diffusion rate of the material of the second active material coating layer 300 is higher than the ion diffusion rate of the material of the first active material coating layer 200. For another example, the second recessed portion 310 is opened on the second active material coating layer 300. On, the second recessed portion 310 is filled with the third active material coating layer 400. The ion diffusion rate of the material of the third active material coating layer 400 is higher than the ion diffusion rate of the material of the second active material coating layer 300.), and because ions will move toward the channel that can achieve faster diffusion, the ions will move toward the position where the first recessed portion 210 and the second recessed portion 310 are located. The staggered arrangement of the first recessed portion 210 and the second recessed portion 310 is conducive to extending the diffusion path of the ions in the electrode piece and achieving uniform diffusion of the ions in the electrode piece.

[0066] In some embodiments, reference Figures 1 to 4 The first recessed portion 210 extends along a straight line from one end of the first active material coating layer 200 to the other end opposite the first active material coating layer 200; the second recessed portion 310 extends along a straight line from one end of the second active material coating layer 300 to the other end opposite the second active material coating layer 300. The groove width W1 of the first recessed portion 210 satisfies the following conditions: 0.5um≤W1≤2000um; the groove width W2 of the second recessed portion 310 satisfies the following conditions: 0.5um≤W2≤2000um. For example, the value of W1 can be 0.5um, 100um, 1000um, 2000um, and so on. The value of W2 can be 0.5um, 100um, 1000um, 2000um, and so on.

[0067] Specifically, in this embodiment, since the sizes of the first recessed portion 210 and the second recessed portion 310 are between the micron level, while ensuring the processing accuracy, it has a high processing difficulty. Therefore, the first recessed portion 210 and the second recessed portion 310 are designed to be a straight line structure, which is conducive to the processing and forming of the first recessed portion 210 and the second recessed portion 310 (during processing, the processing equipment only needs to move along a straight line, or the pole piece only needs to move along a straight line), reducing the processing difficulty of the first recessed portion 210 and the second recessed portion 310.

[0068] Furthermore, in some embodiments, the first recessed portion 210 and the second recessed portion 310 may also adopt other structural forms. For example, the first recessed portion 210 and the second recessed portion 310 may adopt a broken line structural form, the first recessed portion 210 and the second recessed portion 310 may also adopt a polygonal (such as a rectangular, hexagonal, etc.) structural form, and the first recessed portion 210 and the second recessed portion 310 may also adopt a grid structural form.

[0069] Furthermore, when the first recessed portion 210 and the second recessed portion 310 are in a polygonal structure, the area S of the first recessed portion 210 and the second recessed portion 310 satisfies: 0.25 mm 2 ≤S≤25mm 2 For example, the value of S can be 0.25 mm. 2 , 5mm 2 , 10mm 2 , 20mm 2 , 25mm 2 etc.

[0070] In some embodiments, reference Figure 3 and Figure 4 The first active material coating layer 200 is provided with a plurality of first recessed portions 210 along the length direction of the electrode; the second active material coating layer 300 is provided with a plurality of second recessed portions 310 along the length direction of the electrode. The groove spacing L1 between two adjacent first recessed portions 210 satisfies the following conditions: 0.5mm≤L1≤8mm; the groove spacing L2 between two adjacent second recessed portions 310 satisfies the following conditions: 0.5mm≤L2≤8mm. For example, the value of L1 can be 0.5mm, 2mm, 4mm, 6mm, 8mm, etc. The value of L2 can be 0.5mm, 2mm, 4mm, 6mm, 8mm, etc.

[0071] Specifically, in this embodiment, a plurality of first recessed portions 210 are provided on the first active material coating layer 200, and the plurality of first recessed portions 210 are each filled with the second active material coating layer 300; a plurality of second recessed portions 310 are provided on the second active material coating layer 300, and the plurality of second recessed portions 310 are each filled with the third active material coating layer 400. Such a structure is beneficial for lithium ions to rapidly migrate and diffuse between layers of the electrode along the active material materials with high diffusion rates filled in the plurality of recessed portions, and at the same time, is beneficial for lithium ions to uniformly diffuse between layers of the electrode along the active material materials with high diffusion rates filled in the plurality of recessed portions, thereby improving the fast charging performance of the electrode.

[0072] In some embodiments, reference Figure 2The coating thickness D1 of the first active material coating layer 200 satisfies the following conditions: 3.5 μm ≤ D1 ≤ 60 μm; the coating thickness D2 of the second active material coating layer 300 satisfies the following conditions: 2 μm ≤ D2 ≤ 60 μm; and the coating thickness D3 of the third active material coating layer 400 satisfies the following conditions: 2 μm ≤ D3 ≤ 60 μm. For example, the value of D1 can be 3.5 μm, 10 μm, 30 μm, 45 μm, 60 μm, etc. The value of D2 can be 2 μm, 10 μm, 30 μm, 45 μm, 60 μm, etc. The value of D3 can be 2 μm, 10 μm, 30 μm, 45 μm, 60 μm, etc.

[0073] Specifically, in this embodiment, the coating thicknesses of the first active material coating layer 200, the second active material coating layer 300, and the third active material coating layer 400 are set within the above range, which can not only ensure that lithium ions can migrate and diffuse in the electrode, but also reduce the thickness of the electrode, making the electrode lighter and thinner.

[0074] Correspondingly, another embodiment of the present invention further provides a battery cell, which includes the electrode in any of the above embodiments.

[0075] Correspondingly, another embodiment of the present invention further provides an electronic device, which includes the battery cell in any of the above embodiments.

[0076] Specifically, in this embodiment, the battery cell and electronic device using the above-mentioned electrode piece are beneficial to improving the fast charging performance of the battery cell and electronic device, thereby helping to improve the dynamic performance of the battery cell and electronic device.

[0077] Thanks to the improvement of the above-mentioned electrode piece, the battery cell and electronic device of this embodiment have the same technical effects as the above-mentioned electrode piece, which will not be described in detail here.

[0078] It should be noted that other contents of the electrode, battery cell and electronic device disclosed in the present invention can be found in the prior art and will not be described in detail here.

[0079] The above are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A pole piece, characterized in that: include: a current collector, the current collector comprising a first wall; a first active material coating layer, the first active material coating layer being disposed on the first wall surface along a first direction, and a first recessed portion being disposed on a side of the first active material coating layer facing away from the first wall surface; a second active material coating layer, the second active material coating layer being disposed along the first direction on a side of the first active material coating layer facing away from the first wall surface, the second active material coating layer filling the first recessed portion, and a second recessed portion being disposed on a side of the second active material coating layer facing away from the first active material coating layer; a third active material coating layer, the third active material coating layer being disposed along the first direction on a side of the second active material coating layer facing away from the first active material coating layer, and the third active material coating layer filling the second recessed portion; The ion diffusion rate of the material of the third active material coating layer is higher than that of the material of the second active material coating layer, and the ion diffusion rate of the material of the second active material coating layer is higher than that of the material of the first active material coating layer.

2. The pole piece according to claim 1, characterized in that: The capacitance of the material of the first active material coating layer is higher than the capacitance of the materials of the second active material coating layer and the third active material coating layer.

3. The pole piece according to claim 1, characterized in that: The first recessed portion extends from one end of the first active material coating layer to the other end opposite to the first active material coating layer along the width direction of the electrode piece; the second recessed portion extends from one end of the second active material coating layer to the other end opposite to the second active material coating layer along the width direction of the electrode piece.

4. The pole piece according to claim 1, characterized in that: The first recessed portion extends from the first active material coating layer to the first wall surface along the first direction; the second recessed portion extends from the second active material coating layer to the first active material coating layer along the first direction.

5. The pole piece according to claim 1, characterized in that: The first recessed portions and the second recessed portions are arranged alternately.

6. The pole piece according to claim 3, characterized in that: The first recessed portion extends along a straight line from one end of the first active material coating layer to the other end opposite to the first active material coating layer; the second recessed portion extends along a straight line from one end of the second active material coating layer to the other end opposite to the second active material coating layer; The groove width W1 of the first recessed portion satisfies: 0.5um≤W1≤2000um; the groove width W2 of the second recessed portion satisfies: 0.5um≤W2≤2000um.

7. The pole piece according to claim 1, characterized in that: The first active material coating layer is provided with a plurality of first recessed portions along the length direction of the pole piece; the second active material coating layer is provided with a plurality of second recessed portions along the length direction of the pole piece; The groove spacing L1 between two adjacent first recessed portions satisfies: 0.5 mm ≤ L1 ≤ 8 mm; the groove spacing L2 between two adjacent second recessed portions satisfies: 0.5 mm ≤ L2 ≤ 8 mm.

8. The pole piece according to claim 1, characterized in that: The coating thickness D1 of the first active material coating layer satisfies: 3.5um≤D1≤60um; the coating thickness D2 of the second active material coating layer satisfies: 2um≤D2≤60um; and the coating thickness D3 of the third active material coating layer satisfies: 2um≤D3≤60um.

9. A battery cell, characterized in that: A pole piece comprising any one of claims 1 to 8.

10. An electronic device, characterized in that Including the battery cell according to claim 9.

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